JP2006258963A - Electrophotographic toner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic toner which is excellent in dispersibility of a crystalline resin and is excellent in both of low-temperature fixability and durability and a method for manufacturing the same. <P>SOLUTION: The electrophotographic toner is obtained by using a toner composition containing raw materials containing the crystalline resin, a non-crystalline resin and a colorant and a powder derived from the raw materials and by a method having a melt kneading process, a cooling process, a pulverizing process, a classifying process, and a surface treating process, wherein the content of the crystalline resin in the toner is 5 to 50wt%. and the volume medium particle diameter of the powder derived from the raw materials is 0.5 to 8 μm. The method for manufacturing the same is also provided. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electrophotographic toner used for developing a latent image formed in an electrophotographic method, an electrostatic recording method, an electrostatic printing method, and the like, and a method for producing the same.

  One of the characteristics required for an electrophotographic toner is low-temperature fixability. From the viewpoint of improving low-temperature fixability, many toners containing a crystalline resin have been studied. Among these, from the viewpoint of developing low temperature fixability and improving durability, the dispersibility of the crystalline resin is very important. The kneading method (see Patent Document 1), the monomer composition of the crystalline resin (see Patent Document 2). ) Examination from various viewpoints such as mixing of crystalline resin and amorphous resin in a reaction vessel (see Patent Document 3), grafting of crystalline resin and amorphous resin (see Patent Document 4), etc. Has been.

However, the method of Patent Document 1 requires a special kneading machine, and the method of Patent Documents 2 and 4 changes the characteristics of the crystalline resin itself, which is limited in terms of monomer blending, etc. The technique of Document 3 has drawbacks such as insufficient dispersion of the crystalline resin.
JP 2002-287426 A JP 2002-284866 A JP 2003-84493 A Japanese Patent Laid-Open No. 62-299859

  An object of the present invention is to provide an electrophotographic toner excellent in dispersibility of a crystalline resin and excellent in both low-temperature fixability and durability, and a method for producing the same.

The present invention
[1] Using a toner composition containing a raw material containing a crystalline resin, an amorphous resin and a colorant and a powder derived from the raw material, a melt-kneading step, a cooling step, a pulverizing step, a classification step, and a surface treatment step An electrophotographic toner obtained by a method having a volume-median particle size (D ₅₀ ) of the powder derived from the raw material, wherein the content of the crystalline resin in the toner is 5 to 50% by weight. An electrophotographic toner having a thickness of 0.5 to 8 μm, and a toner composition comprising [2] a raw material containing a crystalline resin, an amorphous resin and a colorant, and a powder derived from the raw material, and a melt-kneading step, A method for producing an electrophotographic toner having a cooling step, a pulverizing step, a classification step and a surface treatment step, wherein the content of the crystalline resin in the toner is 5 to 50% by weight, and the powder derived from the raw material An electrophotographic toner having a volume-median particle size (D ₅₀ ) of 0.5 to 8 μm The present invention relates to a method for manufacturing a toner.

  The toner for electrophotography of the present invention is excellent in dispersibility of the crystalline resin and exhibits excellent properties in both low-temperature fixability and durability.

The toner for electrophotography of the present invention is characterized in that a toner composition containing a raw material containing a crystalline resin, an amorphous resin and a colorant and a powder derived from the raw material is used. The volume-median particle size (D ₅₀ ) of the powder derived from the raw material is 0.5 to 8 μm, preferably 1 to 6 μm, more preferably 2 to 5 μm. The raw material-derived powder used in the present invention has a crystalline polyester already dispersed, and by using this raw material-derived powder, the crystalline resin is well dispersed, and is excellent in low-temperature fixability and durability. Toner is obtained. In the present specification, the “raw material” of the toner means a raw material constituting the toner, such as a resin and a colorant, and the “toner composition” means a powder derived from the “raw material” and the “raw material”. And

  Further, it is estimated that the dispersibility of the crystalline resin in the toner is lowered because the melt viscosity of the crystalline resin is low and agglomerates during kneading, so that the share during kneading is reduced. In the invention, the detailed reason is unclear, but because the aggregates are reduced from the initial stage of kneading, the share at the time of kneading is increased, and the effect that the dispersion of the crystalline resin used alone as a raw material is also promoted. Played.

  Another factor that reduces the dispersibility of the crystalline resin is that the crystalline resin does not melt easily during kneading, but the powder containing the crystalline resin is a crystalline resin used as a raw material. In addition, there is an effect that the material melts faster than the amorphous resin, and the raw material to be kneaded is rapidly melted.

  The raw material-derived powder used in the present invention is prepared by melt-kneading and pulverizing a raw material containing a crystalline resin, an amorphous resin, a colorant and the like separately from the production of the toner. However, from the viewpoint of low-temperature fixability, durability, and dispersibility of the crystalline resin, it is more preferable that the recovered powder is a recovered powder obtained by collecting the pulverized product discharged in the classification process when the toner is produced. More preferably, it is a recovered powder obtained by recovering the pulverized product discharged as a fine powder in the process.

  The content of the raw material-derived powder in the toner composition is preferably 5 to 50% by weight, more preferably 10 to 40% by weight, and even more preferably 15 to 30% by weight.

  The content of the crystalline resin in the powder derived from the raw material is such that the dispersibility of the crystalline polyester in the finally obtained toner is improved and the addition efficiency of the powder derived from the raw material is improved, that is, a small amount of powder is added. From the viewpoint of obtaining the maximum effect of improving dispersibility, it is preferably higher than the content of the crystalline resin in the finally obtained toner, preferably 5% by weight, more preferably 10% by weight, still more preferably Is preferably 30% by weight. NMR is preferably used as a method for calculating the amount of crystalline polyester in the raw material-derived powder.

  In the present invention, “crystalline” resin refers to a resin having a crystallinity index of 0.6 to 1.5, preferably 0.8 to 1.2, and “amorphous” resin refers to a crystallinity index of greater than 1.5 or 0.6. A resin less than, preferably greater than 1.5. Here, the crystallinity index is a physical property that is an index of the degree of crystallization of the resin, and is defined by the ratio of the softening point to the maximum endothermic peak temperature (softening point / maximum endothermic peak temperature). is there. A resin having a crystallinity index exceeding 1.5 is amorphous, and a resin having a crystallinity index of less than 0.6 has low crystallinity and many amorphous portions. The degree of crystallization can be adjusted by the type and ratio of the raw material monomers, production conditions (for example, reaction temperature, reaction time, cooling rate) and the like. The highest endothermic peak temperature refers to the temperature of the peak on the highest temperature side among the observed endothermic peaks. If the maximum peak temperature is within 20 ° C. from the softening point, the melting point is set, and the peak having a difference from the softening point exceeding 20 ° C. is a peak due to glass transition.

  As the crystalline resin, crystalline polyester is preferable. The crystalline polyester is obtained by using an alcohol component and a carboxylic acid component as raw material monomers and subjecting them to condensation polymerization.

  In the crystalline polyester, the alcohol component preferably contains a monomer that promotes the crystallinity of the resin, such as an aliphatic diol having 2 to 8 carbon atoms.

  Examples of the aliphatic diol having 2 to 8 carbon atoms include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, Examples include 1,7-heptanediol, 1,8-octanediol, neopentyl glycol, 1,4-butenediol, and α, ω-linear alkanediol is particularly preferable.

  From the viewpoint of high crystallinity, the content of the aliphatic diol having 2 to 8 carbon atoms is preferably 80 mol% or more, more preferably 85 mol% or more, and further preferably 90 mol% or more in the alcohol component. Furthermore, it is desirable that one aliphatic diol in them accounts for 70 mol% or more, preferably 80 to 95 mol% in the alcohol component. Among these, 1,4-butanediol is preferably contained in the alcohol component in an amount of preferably 60 mol% or more, more preferably 70 mol% or more, and even more preferably 80 mol% or more.

  As the carboxylic acid component, fumaric acid, adipic acid, oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, sebacic acid, azelaic acid, n-dodecyl succinic acid, n- Aliphatic dicarboxylic acids having 2 to 30 carbon atoms such as dodecenyl succinic acid, preferably 2 to 8; aromatic dicarboxylic acids such as phthalic acid, isophthalic acid and terephthalic acid; alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid; trimellitic acid And trivalent or higher polyvalent carboxylic acids such as pyromellitic acid. Among these, from the viewpoint of crystallinity, aliphatic dicarboxylic acids are preferable, and aliphatic dicarboxylic acids having 2 to 8 carbon atoms are preferable. In addition, although carboxylic acid, its anhydride, and its alkyl (C1-C3) ester are contained in a carboxylic acid component, In these, carboxylic acid is preferable.

  The content of the aliphatic dicarboxylic acid compound is preferably 70 mol% or more, more preferably 80 to 100 mol%, still more preferably 90 to 100 mol% in the carboxylic acid component.

  The molar ratio of the carboxylic acid component to the alcohol component (carboxylic acid component / alcohol component) in the crystalline polyester is preferably higher in alcohol component than in the carboxylic acid component when increasing the molecular weight of the crystalline polyester. Furthermore, from the viewpoint that the molecular weight of the polyester can be easily adjusted by distilling off the alcohol component during the reduced pressure reaction, it is preferably 0.9 or more and less than 1, and more preferably 0.95 or more and less than 1.

  The polycondensation of the alcohol component and the carboxylic acid component in the production of the crystalline polyester can be performed, for example, in an inert gas atmosphere at a temperature of 120 to 230 ° C. using an esterification catalyst if necessary. it can. In order to increase the strength of the resin, all monomers are charged at once, or a divalent monomer is first reacted to reduce low molecular weight components, and then a trivalent or higher monomer is added and reacted. You may use the method of making it. Further, the reaction may be accelerated by reducing the pressure of the reaction system in the latter half of the polymerization.

  In order to obtain a higher molecular weight crystalline polyester, the molar ratio of the carboxylic acid component and the alcohol component is adjusted as described above, the reaction temperature is increased, the amount of the catalyst is increased, and the dehydration reaction is performed for a long time under reduced pressure. What is necessary is just to select reaction conditions, such as performing. In addition, under high power required for stirring, it is possible to produce a high-viscosity crystalline polyester having a high molecular weight. However, when producing without particularly selecting production equipment, the raw material monomer is a non-reactive low-viscosity resin. A method of reacting with a solvent is also an effective means.

  The softening point of the crystalline polyester is preferably from 70 to 140 ° C, more preferably from 105 to 130 ° C, from the viewpoint of low-temperature fixability.

  The melting point of the crystalline polyester is preferably 60 to 140 ° C., more preferably 70 to 130 ° C., and further preferably 80 to 120 ° C. from the viewpoint of fixability.

  The number average molecular weight of the crystalline polyester is preferably from 3,000 to 10,000, more preferably from 3,500 to 8,500, and even more preferably from 4,000 to 7,000, from the viewpoints of storage stability and productivity.

  The content of the crystalline resin is 5 to 50% by weight in the toner, preferably 7.5 to 40% by weight, and more preferably 10 to 35% by weight. The content of the crystalline resin here means the total content of the crystalline resin including not only the crystalline resin contained alone in the toner composition but also the crystalline resin in the powder derived from the raw material. .

  Examples of amorphous resins include amorphous resins, amorphous polyester polyamides, vinyl resins such as amorphous styrene-acrylic resins, hybrid resins having two or more resin components, and mixtures thereof. Among these, amorphous polyester, amorphous polyester polyamide, and hybrid resin in which an amorphous polyester component and a vinyl resin component are partially chemically bonded from the viewpoint of fixing property and compatibility with crystalline polyester. Is preferred, and amorphous polyester is more preferred.

  Amorphous polyester is also obtained by polycondensation of an alcohol component and a carboxylic acid component as raw material monomers, similarly to crystalline polyester.

  The alcohol component in the amorphous polyester includes polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, etc. Formula (I):

(Wherein R is an alkylene group having 2 or 3 carbon atoms, x and y are positive numbers, and the sum of x and y is 1 to 16, preferably 1.5 to 5.0)
An aromatic diol such as an alkylene oxide adduct of bisphenol A represented by: an aliphatic diol such as ethylene glycol or propylene glycol; a trivalent or higher valent alcohol such as glycerin or pentaerythritol.

  Among the alcohol components, monomers that promote the amorphization of resins such as aromatic diols such as alkylene oxide adducts of bisphenol A are preferred, and from the viewpoint of chargeability, bisphenols represented by formula (I) are preferred. The content of the alkylene oxide adduct of A is preferably 50 mol% or more, more preferably 70 mol% or more, further preferably 90 mol% or more in the alcohol component.

  As the carboxylic acid component, aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid; oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, adipic acid, Aliphatic dicarboxylic acids such as sebacic acid, azelaic acid, n-dodecyl succinic acid and n-dodecenyl succinic acid; cycloaliphatic dicarboxylic acids such as cyclohexanedicarboxylic acid; trivalent or higher polyvalent carboxylic acids such as trimellitic acid and pyromellitic acid And anhydrides of these acids, alkyl (C1-C3) esters, and the like. Among these, aromatic carboxylic acid compounds are preferable from the viewpoint of chargeability. From the viewpoint of safety, aliphatic carboxylic acid compounds are preferred, and fumaric acid is more preferred. In addition, in this invention, a carboxylic acid compound points out dicarboxylic acid, its anhydride, and its alkyl (C1-C3) ester.

  Further, the alcohol component and the carboxylic acid component may appropriately contain a monovalent alcohol and a monovalent carboxylic acid compound from the viewpoint of adjusting the molecular weight.

  The polycondensation of the alcohol component and the carboxylic acid component in producing the amorphous polyester is performed at a temperature of 180 to 250 ° C., for example, in an inert gas atmosphere, if necessary, using an esterification catalyst. Can do.

  In addition to the polyhydric alcohol component and polyvalent carboxylic acid component, the amorphous polyester polyamide further comprises ethylenediamine, pentamethylenediamine, hexamethylenediamine, diethylenetriamine, iminobispropylamine to form an amide component. Polyamines such as phenylenediamine, xylylenediamine and triethylenetetramine, aminocarboxylic acids such as 6-aminocaproic acid and ε-caprolactam, and aminoalcohols such as propanolamine are used as raw material monomers. Among these, hexamethylenediamine is used. And ε-caprolactam are preferred.

  Amorphous polyester polyamide can also be produced in the same manner as amorphous polyester.

  In the present invention, the hybrid resin may be obtained by using two or more kinds of resins as raw materials, or may be obtained from raw material monomers of one kind of resin and another kind of resin, and two more kinds. Although it may be obtained from a mixture of raw material monomers of the above resins, in order to obtain a hybrid resin efficiently, those obtained from a mixture of raw material monomers of two or more resins are preferred.

  Therefore, as a hybrid resin, raw material monomers of two polymerization resins each having an independent reaction path, preferably, a raw material monomer of a condensation polymerization resin and a raw material monomer of an addition polymerization resin are mixed, and the two polymerization reactions are performed. A resin obtained by carrying out the treatment is preferred, and specifically, a hybrid resin described in JP-A-10-087839 is preferred.

  Typical examples of the condensation polymerization resins include polyesters, polyester polyamides, polyamides, etc. Among them, polyesters are preferable, and typical examples of the addition polymerization resins include vinyl resins obtained by radical polymerization reaction, etc. Is mentioned.

  The softening point of the amorphous resin is preferably 70 to 180 ° C, more preferably 100 to 160 ° C, and the glass transition point is preferably 45 to 80 ° C, more preferably 55 to 75 ° C. The glass transition point is a physical property peculiar to an amorphous resin and is distinguished from the maximum peak temperature of heat of fusion.

  In the present invention, as an amorphous resin, a low softening point resin having a softening point of 70 ° C. or higher and lower than 120 ° C. and a high softening point of 120 ° C. or higher and 160 ° C. or lower from the viewpoint of low temperature fixability and high temperature offset resistance. The softening point resin is preferably used in combination at a weight ratio of 20/80 to 80/20 (low softening point resin / high softening point resin).

  The weight ratio of the crystalline resin to the amorphous resin (crystalline resin / amorphous resin) is preferably 1/99 to 40/60 from the viewpoints of chargeability, storage stability, low-temperature fixability, and durability. / 97 to 35/65 is more preferred, and 5/95 to 30/70 is even more preferred.

  As the colorant in the present invention, a pigment used as a colorant for toner can be used. Carbon black, complex oxide, phthalocyanine blue, permanent brown FG, brilliant first scarlet, pigment green B, rhodamine-B base, solvent red 49, solvent red 146, solvent blue 35, quinacridone, carmine 6B, disazo yellow, etc. These can be used alone or in admixture of two or more.

  The blending amount of the colorant is preferably 1 to 40 parts by weight and more preferably 3 to 10 parts by weight with respect to 100 parts by weight of the binder resin.

  In the present invention, a release agent, a charge control agent, a fluidity improver, a conductivity modifier, an extender, a reinforcing filler such as a fibrous substance, an antioxidant, an anti-aging agent, a cleaning property improver, An additive such as a magnetic material may be blended as a raw material.

  Release agents include natural ester waxes such as carnauba wax and rice wax, synthetic waxes such as polypropylene wax, polyethylene wax and Fischer Tropu, petroleum waxes such as paraffin wax, coal waxes such as montan wax, and alcohols. Examples of the wax include wax, and these may be contained alone or in admixture of two or more. Among these, polypropylene wax is preferable from the viewpoint of offset resistance.

  The compounding amount of the release agent is preferably 0.1 to 20 parts by weight, more preferably 0.5 to 15 parts by weight, and further preferably 1 to 10 parts by weight with respect to 100 parts by weight of the binder resin.

  A toner composition containing a crystalline resin, an amorphous resin, a colorant, and a raw material containing additives such as a mold release agent and a powder derived from the raw material, if necessary. It is preferable to use them by premixing them by such means.

  In the present invention, a known kneader such as a closed kneader, a uniaxial or biaxial extruder, an open roll kneader can be used for melt kneading of the raw materials.

  The kneading temperature is not particularly limited as long as the raw materials are mixed.

  The cooling step is a step of cooling the kneaded product obtained in the melt-kneading step, and the temperature at which the kneaded product is cooled is not particularly limited, and may be appropriately cooled until the kneaded product reaches a pulverizable hardness.

The pulverization step is a step of pulverizing the kneaded product cooled in the cooling step. The pulverization of the cooled kneaded material may be performed at once or divided into a plurality of times. However, from the viewpoint of pulverization efficiency and production efficiency, it is preferable to include coarse pulverization and fine pulverization, and the particle size is set in advance. After roughly pulverizing to a volume-median particle size (D ₅₀ ) of about 10 to 1000 μm, it is preferable to further pulverize the resulting coarsely powdered product in consideration of the intended toner particle size. In the present specification, the volume-median particle size (D ₅₀ ) means a particle size at which the cumulative volume frequency calculated by the volume fraction is 50% when calculated from the smaller particle size.

  An atomizer, a funnel plex, etc. can be used for coarse pulverization of a kneaded material.

  For finely pulverizing the coarsely pulverized product, a jet pulverizer such as a fluidized bed jet mill or an airflow jet mill, a mechanical pulverizer such as a turbo mill, or the like can be used.

The classification process is a process of removing coarse powder and fine powder from the pulverized product obtained in the pulverization process, and collecting particles having a desired particle diameter. The volume median particle size (D ₅₀ ) of the toner of the present invention is preferably 3 to 15 μm.

  Examples of the classifier used in the classification process include an air classifier, an inertia classifier, and a sieve classifier.

  The surface treatment step is a step of mixing the toner with the external additive and attaching the external additive to the toner surface.

  As the external additive, inorganic oxides such as silica, titania, alumina, zinc oxide, magnesium oxide, cerium oxide, iron oxide, copper oxide, and tin oxide are preferable. Is preferred. Further, the surface of the external additive may be subjected to a hydrophobic treatment.

  The blending amount of the external additive is preferably 0.01 to 10 parts by weight, and more preferably 0.1 to 5 parts by weight with respect to 100 parts by weight of the toner to be processed, from the viewpoints of chargeability and fluidity.

  The toner of the present invention is not particularly limited and can be used for any developing method as a single component developing toner alone or as a two component developing toner mixed with a carrier.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited at all by this Example.

[Softening point]
Using a Koka-type flow tester (CFT-500D, manufactured by Shimadzu Corporation), a 1 g sample was dried under reduced pressure for 4 hours, and then heated at a heating rate of 6 ° C / min. A nozzle with a diameter of 1 mm and a length of 1 mm is pushed out, and this draws a plunger drop amount (flow value) -temperature curve of the flow tester, h / 2 when the height of the S-curve is h The temperature corresponding to (the temperature at which half of the resin flows out) is defined as the softening point.

[Maximum endothermic peak temperature and melting point]
Using a differential scanning calorimeter (Seiko Denshi Kogyo Co., Ltd., DSC210), the temperature is raised to 200 ° C, and the sample cooled to 0 ° C at a temperature drop rate of 10 ° C / min is measured at a temperature rise rate of 10 ° C / min . Among the observed endothermic peaks, the temperature of the peak on the highest temperature side is defined as the highest endothermic peak temperature. If the maximum peak temperature is within 20 ° C. from the softening point, the melting point is set, and the peak having a difference from the softening point exceeding 20 ° C. is a peak due to glass transition.

[Glass transition point]
Using a differential scanning calorimeter (Seiko Denshi Kogyo Co., Ltd., DSC210), the temperature is raised to 200 ° C, and the sample cooled to 0 ° C at a temperature drop rate of 10 ° C / min is measured at a temperature rise rate of 10 ° C / min . If the binder resin contains an amorphous resin in addition to the crystalline resin, or if the crystalline resin contains an amorphous part, the peak temperature observed at a temperature lower than the maximum endothermic peak temperature, or the endothermic The temperature at the intersection of the base line extension below the maximum peak temperature and the tangent line indicating the maximum slope from the peak rise to the peak apex is read as the glass transition point.

[Crystallinity index]
The crystallinity index is calculated as the degree of crystallinity from the following formula using the softening point and the maximum peak temperature of endotherm measured according to the above.
Crystallinity index = softening point / maximum endothermic peak temperature

[Acid value]
Measured by the method of JIS K0070.

Production Example 1 of Crystalline Polyester
The raw materials shown in Table 1, 4 g of dibutyltin oxide and 1 g of hydroquinone were placed in a 5-liter four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer and a thermocouple, and reacted at 160 ° C. for 5 hours. Thereafter, the temperature was raised to 200 ° C. and reacted for 1 hour, and further reacted at 8.3 kPa until the desired softening point was reached to obtain a resin a.

Production Example 2 of Crystalline Polyester
The raw materials shown in Table 1 and 4 g of dibutyltin oxide were placed in a 5-liter four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer and a thermocouple, reacted at 160 ° C. for 5 hours, The temperature was raised to 0 ° C. and reacted for 1 hour, and further reacted at 8.3 kPa until the desired softening point was reached to obtain resin b.

Production Example 1 of Amorphous Polyester
Raw materials other than trimellitic acid shown in Table 2 and 4 g of dibutyltin oxide were placed in a 5-liter four-necked flask equipped with a nitrogen introduction tube, dehydration tube, stirrer and thermocouple, and reacted at 230 ° C for 20 hours. And then reacted at 8.3 kPa for 1 hour. Furthermore, trimellitic anhydride was added at 210 ° C. and reacted until the desired softening point was reached to obtain Resin A.

Production Example 2 of Amorphous Polyester
Raw materials other than trimellitic anhydride shown in Table 2, 4 g of dibutyltin oxide and 1 g of hydroquinone were placed in a 5-liter four-necked flask equipped with a nitrogen inlet tube, a dehydrating tube, a stirrer and a thermocouple. After reacting over time, it was reacted at 8.3 kPa for 1 hour. Furthermore, trimellitic anhydride was added at 210 ° C. and reacted until the desired softening point was reached to obtain Resins B and C.

Production Examples 1 to 6 of Toner Without Surface Treatment Step (hereinafter referred to as untreated toner)
[Preliminary kneading process]
Binder resin shown in Table 3, colorant “Regal 330R” (Cabot) 4 parts by weight, charge control agent “Bontron S-34” (Orient Chemical Industries) 1 part, polypropylene wax “SP-105” 1 part by weight (manufactured by Sasol, melting point: 105 ° C.) and 1 part by weight of polyethylene wax “Paraflint C80” (manufactured by Sasol, melting point: 82 ° C.) were stirred with a Henschel mixer for 5 minutes.

[Melting and kneading process]
The obtained mixture was melt-kneaded using a co-rotating twin screw extruder having a total length of 1560 mm, a screw diameter of 42 mm, and a barrel inner diameter of 43 mm. The roll rotation speed was 200r / min. The set temperature in the roll was 100 ° C., the outlet temperature of the kneaded product was about 150 ° C., the feed rate of the mixture was 10 kg / h, and the average residence time was about 18 seconds.

[Cooling, grinding and classification process]
The obtained kneaded product was cooled and coarsely pulverized, then finely pulverized by a jet mill and classified to obtain an untreated toner having a volume median particle size (D ₅₀ ) of 7.5 μm.

Production Examples 7 to 10 of Untreated Toner
Except for the binder resin and raw material-derived powder shown in Table 3, the same colorant, charge control agent and wax as in the untreated toner production example 1 were used, and the same as in the untreated toner production example 1. Thus, an untreated toner was obtained.

Production Example 11 of Untreated Toner
The same coloring as in Production Example 1 of Untreated Toner, except that 35 parts by weight of Resin C, 28 parts by weight of Resin B, 14 parts by weight of Resin a, and 30 parts by weight of recovered powder obtained during the production of Untreated Toner 2 were used. An untreated toner having a volume-median particle size (D ₅₀ ) of 7.7 μm was obtained in the same manner as in Production Example 1 of untreated toner using an agent, a charge control agent and a wax. The recovered powder used was obtained by recovering the fine powder removed in the classification step when the untreated toner 2 was produced. The volume median particle size (D ₅₀ ) was measured and found to be 2.6 μm. Further, the content of the resin a in the recovered powder was calculated using NMR, and it was 27% by weight.

Examples 1-5 and Comparative Examples 1-3
[Surface treatment process]
Each 100 parts by weight of the untreated toner shown in Table 4 includes 1 part by weight of hydrophobic silica “SI-Y” (manufactured by Nippon Aerosil Co., Ltd.) and 0.5 part by weight of hydrophobic silica “H2000” (manufactured by Clariant). Was added and mixed with a Henschel mixer to obtain a toner.

  Using the developer obtained by mixing 3 parts by weight of each of the obtained toners and 97 parts by weight of a silicon-coated ferrite carrier (manufactured by Kanto Denka Kogyo Co., Ltd.) having an average particle size of 90 μm, the durability of the toner was determined according to the following method And low-temperature fixability were evaluated. The results are shown in Table 4.

〔durability〕
The developer was mounted on “Pretail 50” (manufactured by Ricoh Co., Ltd.), and an image with a printing rate of 5% was continuously printed for 5 hours, and then the developer was taken out. Only the toner was sucked from the developer using a sieve having an opening of 32 μm, and the carrier was left. Measure the amount of carbon in the remaining carrier using a carbon analyzer “EMIA-110” (Horiba) and determine the difference from the amount of carbon in the carrier measured before mixing with the toner in advance. Durability was evaluated according to the evaluation criteria. That is, it can be determined that the larger the difference in the carbon amount, the more toner is attached to the carrier and the lower the toner durability.
(Evaluation criteria)
◎: Carbon content difference is less than 0.1 ○: Carbon content difference is 0.1 or more, less than 0.2 ×: Carbon content difference is 0.2 or more

(Low temperature fixability)
A developer was mounted on a copying machine “AR-505” (manufactured by Sharp Corporation), and an unfixed image (2 cm × 12 cm) having a toner adhesion amount of 0.6 mg / cm ² was obtained. The fixing machine (fixing speed: 150mm / sec) improved so that the fixing machine of the copier "AR-505" (manufactured by Sharp Corporation) can be fixed off-line. The fixing test was conducted while raising the temperature. As the fixing paper, “CopyBond SF-70NA” (manufactured by Sharp Corporation, 75 g / m ² ) was used.

  “Unicelophane tape” (Mitsubishi Pencil Co., Ltd., width: 18 mm, JIS Z-1522) was applied to the image fixed at each temperature, passed through a fixing roll set at 30 ° C., and then the tape was peeled off. The optical reflection density before and after the tape is peeled off is measured using a reflection densitometer “RD-915” (manufactured by Macbeth), and the ratio of both (after peeling / before sticking) first exceeds 70%. The temperature of the roller was set as the minimum fixing temperature, and the low temperature fixing property was evaluated according to the following evaluation criteria.

(Evaluation criteria)
A: Minimum fixing temperature is less than 140 ° C. ○: Minimum fixing temperature is 140 ° C. or higher and lower than 160 ° C. ×: Minimum fixing temperature is 160 ° C. or higher.

  From the above results, it can be seen that the toners of the examples are excellent in both low-temperature fixability and durability. On the other hand, the toners of Comparative Examples 1 and 3 are inferior in durability and low-temperature fixability. However, the use of crystalline polyester decreases the melt viscosity and aggregates during kneading, and the kneading share is reduced. This is presumably due to the result that the dispersibility deteriorated due to the decrease. Further, the toner of Comparative Example 2 has a practical fixing level, which is common in that the combined crystalline polyester and amorphous polyester have fumaric acid as the main component of the carboxylic acid component. Therefore, it is presumed that the result is that the compatibility of the resin is increased. However, since the powder derived from the raw material is not used and the decrease in melt viscosity caused by the crystalline polyester is not improved, the durability is lacking as in Comparative Examples 1 and 3.

  The toner for electrophotography of the present invention is suitably used for developing a latent image formed in electrophotography, electrostatic recording method, electrostatic printing method and the like.

Claims (8)

A method comprising a toner composition comprising a raw material containing a crystalline resin, an amorphous resin and a colorant and a powder derived from the raw material, and having a melt-kneading step, a cooling step, a pulverizing step, a classification step, and a surface treatment step In which the content of the crystalline resin in the toner is 5 to 50% by weight, and the volume-median particle size (D ₅₀ ) of the powder derived from the raw material is 0.5 to ₅₀ %. An electrophotographic toner of 8 μm.   2. The toner for electrophotography according to claim 1, wherein the content of the crystalline resin in the powder derived from the raw material is higher than the content of the crystalline resin in the toner.   The electrophotographic toner according to claim 1, wherein the crystalline resin contains a crystalline polyester.   The toner for electrophotography according to claim 1, wherein the amorphous resin contains an amorphous polyester.   The toner for electrophotography according to any one of claims 1 to 4, wherein the powder derived from the raw material is a collected powder obtained by collecting the pulverized product discharged in the classification step.   The toner for electrophotography according to any one of claims 1 to 5, wherein the content of the powder derived from the raw material in the toner composition is 5 to 50% by weight.   The electrophotographic toner according to claim 1, further comprising a step of premixing the toner composition before the melt-kneading step. An electron having a melting and kneading step, a cooling step, a pulverizing step, a classification step, and a surface treatment step using a toner composition containing a raw material containing a crystalline resin, an amorphous resin and a colorant and a powder derived from the raw material A method for producing a photographic toner, wherein the content of the crystalline resin in the toner is 5 to 50% by weight, and the volume-median particle size (D ₅₀ ) of the powder derived from the raw material is 0.5 to 8 μm. A method for producing an electrophotographic toner.